Method of making abrasive pads



Oct. 31, 1950 A. w. SCHMIDT ma'mon OF MAKING ABRASIVE PADS Filed Dec.30, 1947 IN VEN TOR.

W, SCHMIDT ARNOLD mam ATTORNEY Patented Oct. 31, 1950 METHOD OF MAKINGABRASIVE PADS Arnold William Schmidt, Delavan, Wis., aseignor to TheGeorge W. Borg Corporation, Delavan, Wis., a corporation of DelawareApplication December 30, 1947, Serial No. 794,549

2 Claims.

The present invention relates in general to abrasive pads, and more inparticular to pads employing steel or other metallic wool as theabrasive medium, and the object of the invention is a new and improvedarticle of this character.

A special object of the invention is a knitted pile fabric, having asteel wool pile, from which abrasive pads of any desired size and shapemay be manufactured.

The invention will be described more in detail in the followingspecification, reference being had to the accompanying drawing, inwhich- Fig. 1 is a top or plan view of an abrasive pad made from myimproved steel wool pile fabric;

-Fig. 2 is a rear view of the same, showing the canvas or duck backingmaterial, also the knitted base of the pile fabric; and

Fig. 3 is an edge view of the abrasive pad, showing the height orthickness of the steel wool pile.

Referring to the drawing, the abrasive pad therein shown is ofrectangular shape and is suitable for hand use. It comprises a piece ofknitted steel wool pile fabric and a backing of woven canvas or ducksecured thereto by means of a suitable cement or other adhesive. At onecorner of the pad the backing material has been left free so that it canbe folded back as seen in Fig. 2 to expose the back of the pile fabric.

The knitted base of the pile fabric is made with the jersey stitch andis indicated at M in Figs. 2 and 3. Mercerized cotton thread may beused, size 2/24, and there may be, for example, or 12 stitches to theinch. The pile is of steel wool, although other metallic wool could beused, and is indicated at E0 in Figs. 1 and 3. The backing material maybe of any suitable canvas or duck and is indicated at I2 in Figs. 2 and3.

The knitted steel wool pile fabric may be manufactured on a combinedknitting and carding machine of the general type shown in the patent toMoore, No. 1,848,370, granted March 8, 1932.

The particular machine used in the manufacture of the pile fabric shownin the drawing comprises a circular latch needle knitting machinemanufactured by the Wildman Manufacturing Company, of Norristown, Pa.,modified by the addition of a pair of feed rollers and four seriallyrelated carding rollers for feeding the steel wool to the needles at theknitting position.

The steel wool is supplied in the form of a continuous roving which istaken up by the feed rollers and passed on to the first of the cardingrollers. These rollers revolve at successively higher speeds, as is wellknown. with the result 2 that the steel wool roving is pulled apart andbroken up as it is transferred from each carding roller to the next inthe series, and is thus prepared for delivery to the needles of theknitting machine. The carding rollers not only prepare the steel wool asdescribed, but they accelerate it by stages until at the final stage itis moving at the proper speed for smooth transfer from the cardingroller to the needles. In the case of the manufacture of wool pilefabrics for overcoats, blankets, etc. the ratio of the speed of the lastcarding roller to the cylinder speed is about 7% or 8 to l, but in themanufacture of my steel wool pile fabric a slower speed for the cardingroller is to be preferred. A speed ratio of 5 to 1 has been found to besatisfactory.

Since the maximum pile thickness or depth is desirable, the speed of thefeed rollers should be adjusted so that the re is fed along about asfast as it can be handled, that is, as fast as the material can be takenoh the final carding roller by the needles. The fibers of steel wool arestraightened out and laid parallel to each other more or less by thecarding operation, sufliciently so that in the knitting operation theneedles are able to seize uniform bunches of steel wool fiber which areincorporated in the stitches of the base fabric along with the thread ofwhich it is formed. The steel wool pile is thus very firmly anchored tothe knitted base fabric. The steel wool is crinkly and resilient,causing the fibers locked in adjacent stitches to become intertwined andmatted together as can be seen in Fig. 1.

Having made a sheet of the steel wool pile fabric of convenient ordesired size, the backing material is applied thereto by means ofsuitable cement or other adhesive. A synthetic latex rubber adhesive hasbeen found to be very satisfactory. Adhesives of this type are cured bya moderate heat treatment and are well known. It may be pointed out thatthe surfaces of the duck i2 and the knitted base material I l are welladapted for joining by an adhesive of this nature, which penetrates wellinto the interstices between the fibres of the materials, and a verygood bond may be secured without difflculty.

Abrasive pads of the desired size and shape may now be punched from thefinished sheet by means of a die. The pads may be square or rectangularas shown in the drawing. Round pads may also be made, having a hole inthe center for attachment to a motor driven arbor.

It will be understood that the pile fabric can be cut up or piecespunched therefrom before the aware:

backing is applied, and in some cases this proeedure will be preferred.

The invention provides an abrasive pad which is superior to anything ofthe kind which has been known before. Attempts have been made in thepast to use steel wool in the manufacture of abrasive pads, but havebeen unsuccessful because with the methods employed, it was not possibleto firmly attach any sizable quantity of the wool to the backingmaterial. This is essential to success, particularly for motor drivenpads. The difnculty is overcome by the present invention, which excelsboth as to the amount of steel wool per unit area of the pad and asregards its secure attachment to the backing material. The solution ofthe attachment problem by incorporating the steel wool as a pile in aknitted pile fabric. which is attached to the backing material by anadhesive, is especially fortunate. The steel wool pile is indestructablylocked in the stitches of the pile fabric and the latter issubstantially inseparably bonded to the backing material, providing anabrasive pad having an exceptionally long life.

The invention having been described, that which is believed to be newand for which the protection of Letters Patent is desired will bepointed out in the appended claims.

I claim:

1. The method of manufacturing stock for abrasive pads, which consistsin making a knitted fabric on a knitting machine. while feeding steelwooliotheneediesofsaidmachinetoincorvorate said steel wool in saidknitted fabric as a pile, and Joining a layer of woven material to thetliaclk of said knitted fabric by means of an ades ve.

2. The method of attaching steel or other metallic wool to heavy wovenmaterial such as duck, which consists in breaking a continuous roving ofmetallic wool by carding, feeding the broken wool to the needles of aknitting machine while making a knitted fabric thereon, whereby saidwool becomes incorporated in the stitches of said fabric to form a pileon one side thereof,

and bonding said woven material to the other side.

of said'fabric by means of an adhesive.

ARNOLD WILLIAM SCHMIDT.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

1. THE METHOD OF MANUFACTURING STOCK FOR ABRASIVE PADS, WHICH CONSISTSIN MAKING A KNITTED FABRIC ON A KNITTING MACHINE, WHILE FEEDING STEELWOOL TO THE NEEDLES OF SAID MACHINE TO INCORPORATE SAID STEEL WOOL INSAID KNITTED FABRIC AS A PILE, AND JOINING A LAYER OF WOVEN MATERIAL TOTHE BACK OF SAID KNITTED FABRIC BY MEANS OF AN ADHESIVE.